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1. A train starts from rest at station A and accelerates uniformly at 3x m s-2 until it reaches a
speed of 30 m s-1
. For the next T seconds the train maintains this constant speed. The
train then retards uniformly at x m s-2 ,until it comes to rest at a station B. The distance
between the stations is 6 km and the time taken from A to B is 5 minutes.

Show that 40/x+ T= 300

i'm sorry i dont know where to start :/

any help would be very appreciated!
2. (Original post by heatabi11)
A train starts from rest at station A and accelerates uniformly at 3x m s-2 until it reaches a
speed of 30 m s-1
. For the next T seconds the train maintains this constant speed. The
train then retards uniformly at x m s-2 ,until it comes to rest at a station B. The distance
between the stations is 6 km and the time taken from A to B is 5 minutes.

Show that 40/x+ T= 300

i'm sorry i dont know where to start :/

any help would be very appreciated!
Sketch a time-velocity graph of this situation.

The first interval has time , the second has , and the third has

The gradient of the first one is and the gradient of the third one is

Rearrange the first one for and substitute it into the second one. Rearrange for the wanted form.
3. (Original post by RDKGames)
Sketch a time-velocity graph of this situation.

The first interval has time , the second has , and the third has

The gradient of the first one is and the gradient of the third one is

Rearrange the first one for and substitute it into the second one. Rearrange for the wanted form.
Thank you ! also how could i work out T and x ?
4. (Original post by heatabi11)
Thank you ! also how could i work out T and x ?
Well for T you know how much it has traveled, and the distance traveled is the area under your graph. So apply the trapezium area and you can find T. Then you can use the part above to find x.

Keep in mind, you need to turn km into m, and minutes into seconds.

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Updated: September 26, 2016
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